Herbicide-tolerant transgenic plants in high yielding commercial wheat cultivars obtained by microprojectile bombardment and selection on Basta

Most of the published work on transgenic wheat has used tissue culture resp onsive varieties such as 'Bobwhite'. The aim of the present study was to pr oduce transgenic lines in modern high-yielding wheat cultivars irrespective of their tissue culture potential, using 'Biolistic' approach. Three of th e highest yielding Indian wheat cultivars, namely CPAN 3004, Sonalika and U P 2338 were chosen for transformation. Stable transgenic plants with bar (c onferring resistance to herbicide Basta) and gus genes were produced in eac h of these cultivars. Earlier developed transformation and regeneration pro tocols for tissue culture responsive lines were modified for obtaining tran sformation frequencies ranging from 0.14 to 0.83%. These frequencies are co mparable with the published reports using the most responsive lines. Analys is of co-segregation patterns for bar and gus genes in the R1 progeny of a CPAN 3004 transformant indicated integration at two different sites in the genome. While both the sites have functional gus gene, only one of these ha s a functional bar gene, giving 15:1 and 3:1 segregation ratios for the two genes, respectively. Expression of bar gene under the maize ubiquitin prom oter was high enough to provide protection against topical application of 2 50 mg/l gluphosinate ammonium, a concentration that killed most of the weed s including Phalaris minor.